TM 9-4120-411-14
4.8 ACCESS FOR TROUBLESHOOTING - CONTINUED.
Figure 4- 8. Access for Troubleshooting.
4.9 LOGIC CONTROL DETAILS. The following paragraphs describe the layout of the pc board as well as the general
function of components and overall unit control logic including system monitoring for diagnostic purposes.
WARNING
Lethal voltage levels are used in operating the FDECU. Disconnecting power will
reset the fault indicators. Therefore it may be necessary to access the pc board
and power box assembly components when power is connected to effectively
diagnose the trouble while the unit is still in the fault mode. Be sure to observe
extreme caution when accessing electrical assembly if power is connected.
The pc board contains high voltage on control circuits as do the contactor coils.
Injury or death can occur if personnel contact any electrical terminal while the unit
is connected to power source.
NOTE
The pc board cannot be tested outside the FDECU.
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